The history of concentrating solar power (CSP) is characterized by a boom-bust pattern caused by policy support changes. Following the 2014–2016 bust phase, the combination of Chinese support and several low-cost projects triggered a new boom phase. We investigate the near- to mid-term cost, industry, market and policy outlook for the global CSP sector and show that CSP costs have decreased strongly and approach cost-competitiveness with new conventional generation. Industry has been strengthened through the entry of numerous new companies. However, the project pipeline is thin: no project broke ground in 2019 and only four projects are under construction in 2020. The only remaining large support scheme, in China, has been canceled. Without additional support soon creating a new market, the value chain may collapse and recent cost and technological advances may be undone. If policy support is renewed, however, the global CSP sector is prepared for a bright future.@en

In the version of this Analysis originally published, the total learning rate for parabolic trough stations with 6–8 hours of thermal storage (Fig. 2b) was calculated to be 25%. After publication, the authors found a code error that caused the learning curve fit function to believe that the first station in the dataset was marked as 1 GW and not 0 GW. As a result, the estimated learning rates for the complete timespan were too high. The correct learning rates should be 2.7% for Fig. 2a and 6.8% for Fig. 2b (instead of 5.2% and 25.2%, respectively). These learning rate fit curves have been updated and the captions have been corrected. For consistency with Fig. 2a, a fit for 2011–2017 has been added to Fig. 2b, showing a learning rate of 17.5% (R2 = 0.337). The text has been modified in the abstract and the sections ‘Observed investment cost development and learning rates’, ‘Policy regime impacts on cost development’ and ‘Conclusions’ to reflect the quantitative changes to the learning rates. Supplementary Notes 1, 3 and 4 and Supplementary Figs. 2, 6 and 7 and their captions have also been updated to reflect the new learning rates. In the caption of Supplementary Fig. 2b, “(2008–2017 learning rate=0.21, R2=0.468)” has been changed to “(2008–2017 learning rate=0.06, R2=0.513; 2011–2017 learning rate=0.079, R2=0.072)”. In the caption of Supplementary Fig. 6b, “(2008–2017 learning rate=0.289, R2=0.715)” has been changed to “(2008–2017 learning rate=0.077, R2=0.631; 2011–2017 learning rate=0.225, R2=0.498)”. In the caption of Supplementary Fig. 7, “(a) parabolic trough (PT) stations with <1 hour thermal storage (2011–2014 learning rate=0.297, R2=0.972 (US$) and learning rate=0.27, R2=0.909 (€)); and (b) PT stations with 6–8 hours of thermal storage (2008–2017 learning rate=0.252, R2=0.621 (US$) and learning rate=0.138, R2=0.502 (€))” has been changed to “(a) parabolic trough (PT) stations with <1 hour thermal storage (2011–2014 learning rate=0.297, R2=0.972 (US$) and 2011–2014 learning rate=0.27, R2=0.909 (€)); and (b) PT stations with 6-8 hours of thermal storage (2011–2017 learning rate=0.175, R2=0.337 (US$) and 2011–2017 learning rate=0.072, R2=0.149 (€))”. The underlying data were correct as originally published and remain unchanged.@en

Concentrating solar power (CSP) capacity has expanded slower than other renewable technologies and its costs are still high. Until now, there have been too few CSP projects to derive robust conclusions about its cost development. Here we present an empirical study of the cost development of all operating CSP stations and those under construction, examining the roles of capacity growth, industry continuity, and policy support design. We identify distinct CSP expansion phases, each characterized by different cost pressure in the policy regime and different industry continuity. In 2008-2011, with low cost pressure and following industry discontinuity, costs increased. In the current phase, with high cost pressure and continuous industry development, costs decreased rapidly, with learning rates exceeding 20%. Data for projects under construction suggest that this trend is continuing and accelerating. If support policies and industrial structure are sustained, we see no near-term factors that would hinder further cost decreases.@en